A method for compensating apd temperature drift in Raman distributed optical fiber temperature measurement system

Abstract

The invention discloses a method for compensating APD temperature drift in a Raman distributed optical fiber temperature measurement system. The optical fiber temperature measurement system includes a pulse laser, a wavelength division multiplexing module, a reference optical fiber module, a first APD detector module, A second APD detector module, an analog-to-digital conversion acquisition module and a control center. The invention can eliminate the influence of the gain fluctuation caused by the temperature change of the working environment on the APD detector module and the subsequent amplifier circuit, and improves the temperature measurement accuracy of the measurement system; at the same time, it avoids the temperature measurement of the global calibration of the global sensing optical fiber, and only needs to Measure the temperature of the reference optical fiber with a local length of 10m to 300m, which greatly simplifies the engineering operation.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a method for compensating APD temperature drift in a Raman distributed optical fiber temperature measurement system. Background technique [0002] The Raman distributed optical fiber temperature measurement system uses optical fiber as a temperature sensing element. Each point on the optical fiber is a temperature measurement element, which can realize simultaneous temperature measurement at multiple points in a wide range, and the temperature-sensing optical fiber can be pressed according to actual needs. Arranged in a certain spatial position, so that the spatial measurement of the three-dimensional temperature field can be realized. This emerging temperature measurement technology is based on the Raman scattering characteristics of optical fibers, combined with the principle of optical fiber laser radar to realize distributed temperature detection. [0003] Raman...

AI Technical Summary

Problems solved by technology

Avalanche photodiodes (APDs) have been widely used in the field of photodetection technology due to their extremely high sensitivity gain. In optical fiber sensing systems, APDs are commonly used as the preferred detectors for extremely weak light signals, but the gain of APDs is affected by temperature. The impact is obvious, so the temperature drift of the APD gain will cause the deterioration of the measurement accuracy when detecting the intensity type signal, and seriously affect the stability of the optical fiber sensing system

Since the scattered light of anti-Stokes and Stokes needs to be photoelectrically converted and amplified by the APD detector and the amplifier circuit, when the ambient temperature changes and the gain of the APD detector and the amplifier circuit changes, if it is not correct Compensating the deviation caused by it will lead to an increase in the demodulation error and reduce the temperature measurement accuracy of the system

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